59121-74-3Relevant articles and documents
A silicododecamolybdate/pyridinium-tetrazole hybrid molecular salt as a catalyst for the epoxidation of bio-derived olefins
Nunes, Martinique S.,Neves, Patrícia,Gomes, Ana C.,Cunha-Silva, Luís,Lopes, André D.,Valente, Anabela A.,Pillinger, Martyn,Gon?alves, Isabel S.
, (2020/11/27)
The hybrid polyoxometalate (POM) salt (Hptz)4[SiMo12O40]?nH2O (1) (ptz = 5-(2-pyridyl)tetrazole) has been prepared, characterized by X-ray crystallography, and examined as a catalyst for the epoxidation of cis-cyclooctene (Cy) and bio-derived olefins, namely dl-limonene (Lim; a naturally occurring monoterpene found in the rinds of citrus fruits), methyl oleate and methyl linoleate (fatty acid methyl esters (FAMEs) obtained by transesterification of vegetable oils). The crystal structure of 1 consists of α-Keggin-type heteropolyanions, [SiMo12O40]4-, surrounded by space-filling and charge-balancing 2-(tetrazol-5-yl)pyridinium (Hptz+) cations, as well as by a large number of water molecules of crystallization (n = 9). The water molecules mediate an extensive three-dimensional (3D) hydrogen-bonding network involving the inorganic anions and organic cations. For the epoxidation of the model substrate Cy in a nonaqueous system (tert-butylhydroperoxide as oxidant), the catalytic performance of 1 (100% epoxide yield at 24 h, 70 °C) was superior to that of the tetrabutylammonium salt (Bu4N)4[SiMo12O40] (2) (63% epoxide yield at 24 h), illustrating the role of the counterion Hptz+ in enhancing catalytic activity. The hybrid salt 1 was effective for the epoxidation of Lim (69%/85% conversion at 6 h/24 h) and the FAMEs (87–88%/100% conversion at 6 h/24 h), leading to useful bio-based products (epoxides, diepoxides and diol products).
Selective Catalytic Synthesis of 1,2- and 8,9-Cyclic Limonene Carbonates as Versatile Building Blocks for Novel Hydroxyurethanes
Maltby, Katarzyna A.,Hutchby, Marc,Plucinski, Pawel,Davidson, Matthew G.,Hintermair, Ulrich
supporting information, p. 7405 - 7415 (2020/05/25)
The selective catalytic synthesis of limonene-derived monofunctional cyclic carbonates and their subsequent functionalisation via thiol–ene addition and amine ring-opening is reported. A phosphotungstate polyoxometalate catalyst used for limonene epoxidation in the 1,2-position is shown to also be active in cyclic carbonate synthesis, allowing a two-step, one-pot synthesis without intermittent epoxide isolation. When used in conjunction with a classical halide catalyst, the polyoxometalate increased the rate of carbonation in a synergistic double-activation of both substrates. The cis isomer is shown to be responsible for incomplete conversion and by-product formation in commercial mixtures of 1,2-limomene oxide. Carbonation of 8,9-limonene epoxide furnished the 8,9-limonene carbonate for the first time. Both cyclic carbonates underwent thiol–ene addition reactions to yield linked di-monocarbonates, which can be used in linear non-isocyanate polyurethanes synthesis, as shown by their facile ring-opening with N-hexylamine. Thus, the selective catalytic route to monofunctional limonene carbonates gives straightforward access to monomers for novel bio-based polymers.
Systematic synthetic study of four diastereomerically distinct limonene-1,2-diols and their corresponding cyclic carbonates
Morikawa, Hiroshi,Yamaguchi, Jun-ichi,Sugimura, Shun-ichi,Minamoto, Masato,Gorou, Yuuta,Morinaga, Hisatoyo,Motokucho, Suguru
supporting information, p. 130 - 136 (2019/01/30)
In order to produce versatile and potentially functional terpene-based compounds, a (R)-limonene-derived diol and its corresponding five-membered cyclic carbonate were prepared. The diol (cyclic carbonate) comprises four diastereomers based on the stereochemical configuration of the diol (and cyclic carbonate) moiety. By choosing the appropriate starting compounds (trans- and cis-limonene oxide) and conditions, the desired diastereomers were synthesised in moderate to high yields with, in most cases, high stereoselectivity. Comparison of the NMR data of the obtained diols and carbonates revealed that the four different diastereomers of each compound could be distinguished by reference to their characteristic signals.
